Ceph An OSD is marked as out, meaning it is not part of the active cluster and not serving data.

The OSD might be down or manually marked out due to maintenance or failure.

Understanding Ceph and Its Purpose

Ceph is a highly scalable distributed storage system designed to provide excellent performance, reliability, and scalability. It is widely used for cloud infrastructure, providing object, block, and file storage in a unified system. Ceph's architecture is based on a cluster of OSDs (Object Storage Daemons), which store data and handle data replication, recovery, and rebalancing.

Identifying the Symptom: OSD_OUT

When an OSD is marked as 'out', it is not part of the active cluster and is not serving data. This can lead to reduced redundancy and potential data availability issues if not addressed promptly. The cluster's health status may show warnings or errors related to the OSD being out.

Exploring the Issue: Why is an OSD Marked as Out?

An OSD can be marked as 'out' for several reasons, including:

The OSD is down due to hardware failure or network issues.
The OSD was manually marked out for maintenance purposes.
Automatic marking by Ceph due to prolonged unavailability.

When an OSD is out, it is excluded from data placement calculations, which can affect the cluster's overall performance and data redundancy.

Steps to Fix the OSD_OUT Issue

Step 1: Verify OSD Status

First, check the status of the OSD using the following command:

ceph osd tree

This command will display the status of all OSDs in the cluster. Look for the OSD marked as 'out'.

Step 2: Check OSD Health

Ensure that the OSD is healthy and ready to be re-added to the cluster. You can check the OSD logs for any errors or issues:

journalctl -u [email protected]

Replace <osd-id> with the actual OSD ID.

Step 3: Re-add the OSD to the Cluster

If the OSD is healthy, you can re-add it to the cluster using the following command:

ceph osd in <osd-id>

This command will mark the OSD as 'in', allowing it to participate in data placement and recovery operations.

Step 4: Monitor Cluster Health

After re-adding the OSD, monitor the cluster's health to ensure that it returns to a healthy state. Use the following command to check the cluster status:

ceph health

For more detailed information, refer to the Ceph documentation on managing OSDs.

Conclusion

Addressing an OSD_OUT issue promptly is crucial to maintaining the health and performance of a Ceph cluster. By following the steps outlined above, you can ensure that your OSDs are correctly integrated into the cluster, providing the necessary redundancy and data availability.

For further reading, visit the official Ceph website or the Ceph documentation for more insights into managing and troubleshooting Ceph clusters.

Never debug

Ceph

manually again

Let Dr. Droid create custom investigation plans for your infrastructure.

Automate Debugging for

Ceph

See how Dr. Droid creates investigation plans for your infrastructure.

MORE ISSUES

PGs are undergoing repair operations, often due to data inconsistencies or corruption.

Ceph Monitor disk I/O error affecting Ceph monitor functionality.

A monitor's disk is experiencing I/O errors.

Ceph OSD_DISK_IO_ERROR

An OSD's disk is experiencing I/O errors, affecting its ability to store data.

Ceph MDS_DISK_FULL

The MDS's disk is full, affecting its ability to function properly.

Ceph RADOS Gateway experiencing performance issues due to network problems.

Network configurations or connectivity issues affecting RADOS Gateway communication.

Ceph The RADOS Gateway service is down, affecting object storage access.

The RADOS Gateway service is not running, which could be due to network issues, resource constraints, or configuration errors.

Ceph Network congestion is affecting OSD communication, leading to performance degradation.

Network congestion is affecting OSD communication, leading to performance degradation.

Ceph PG_BACKFILL

PGs are undergoing backfill operations, often due to OSD additions or recoveries.

Ceph POOL_QUOTA_EXCEEDED

A pool has exceeded its configured quota, preventing further writes.

Ceph Monitor experiencing high CPU usage

A monitor is experiencing high CPU usage, affecting its performance.

Ceph OSD_DISK_SLOW

An OSD's disk is performing slowly, affecting its ability to serve data.

Ceph MDS_NETWORK_ISSUE

Network issues are affecting MDS communication, leading to performance problems.

Ceph OSD is experiencing high CPU usage.

An OSD is experiencing high CPU usage, affecting its performance.

Ceph Authentication failures when accessing the RADOS Gateway.

Incorrect credentials or configuration settings.

Ceph PG_SCRUB_ERRORS

Errors occurred during PG scrubbing, possibly due to data corruption.

Ceph A monitor is consuming excessive memory, possibly due to a memory leak.

A monitor is consuming excessive memory, possibly due to a memory leak.

Ceph High network latency is affecting OSD performance.

High network latency

Ceph RGW_BUCKET_NOT_FOUND

A requested bucket does not exist in the RADOS Gateway.

Ceph The MDS is consuming excessive memory, possibly due to a memory leak.

The MDS is consuming excessive memory, possibly due to a memory leak.

Ceph An OSD is consuming excessive memory, possibly due to a memory leak.

The OSD process may have a memory leak, causing it to consume more memory than expected.

Ceph OSD_DISK_FAILURE

An OSD's disk has failed, affecting its ability to store data.

Ceph PG_INCOMPLETE

PGs are incomplete, often due to missing OSDs or data corruption.

Ceph Monitor nodes are experiencing communication issues, leading to quorum problems.

Network issues are affecting monitor communication.

An MDS instance is stale, possibly due to network issues or failover problems.

Ceph Monitor daemon crash in Ceph cluster.

A monitor daemon has crashed, possibly due to software bugs or resource exhaustion.

Ceph An OSD's journal is full, affecting its ability to process writes.

The journal size is insufficient for the current workload, or there may be a configuration issue.

Ceph POOL_NOT_FOUND

A requested pool does not exist, possibly due to configuration errors or deletion.

Ceph OSD_NETWORK_ISSUE

Network issues are affecting OSD communication, leading to degraded performance or failures.

Ceph An OSD is repeatedly going up and down, often due to unstable hardware or network issues.

Unstable hardware or network issues causing OSD flapping.

The RADOS Gateway is experiencing slow performance, possibly due to high load or resource constraints.

Ceph The MDS is overloaded, affecting CephFS performance.

The MDS is overloaded due to high metadata operations, insufficient resources, or improper configuration.

Ceph OSD daemon crash

Software bugs or hardware issues

Ceph PG_UNCLEAN

PGs are not in a clean state, often due to OSD failures or ongoing recovery operations.

Ceph Monitor disk is full, causing operational issues.

The monitor's disk has reached its storage capacity limit.

Ceph INCOMPATIBLE_CLIENT error encountered when a client tries to connect to the Ceph cluster.

A client is using an incompatible version of the Ceph software.

Ceph SLOW_REQUESTS

Requests to the cluster are slow, possibly due to high load or resource contention.

Ceph RADOSGW_UNAVAILABLE

The RADOS Gateway (RGW) is unavailable, affecting object storage access.

Ceph MDS failover is not occurring as expected.

Configuration issues with MDS or improperly configured standby MDS instances.

The Metadata Server (MDS) is down, affecting CephFS operations.

Ceph Communication issues between Ceph components due to network partition.

A network partition is causing communication issues between Ceph components.

Ceph CRUSH_MAP_ERROR

Errors in the CRUSH map configuration, potentially causing data placement issues.

Ceph Authentication failure between Ceph components.

Incorrect keyring or configuration settings.

Ceph An OSD has reached its full capacity, preventing further writes.

An OSD has reached its full capacity, preventing further writes.

Operations are taking longer than expected, possibly due to high load, network latency, or hardware bottlenecks.

Ceph MON_QUORUM_LOST

The monitor quorum is lost, often due to network partitions or multiple monitor failures.

PGs are stuck in a non-active state, possibly due to OSDs being down or network partitions.

Ceph PG_DEGRADED

Placement Groups (PGs) are not fully replicated, often due to OSD failures or network issues.

Ceph An OSD is marked as out, meaning it is not part of the active cluster and not serving data.

The OSD might be down or manually marked out due to maintenance or failure.

Ceph An OSD is marked as down in the Ceph cluster.

Network issues, hardware failure, or the OSD daemon crashing.

Backed by

Platform

Resources

Contact

Connect

Made with ❤️ in & 🏢

Doctor Droid